Incandescent-electric-lamp socket



(No Model.)

G. E. EGAN.

INGANDBSOBNT ELECTRIC LAMP SOCKET. No. 399,748. Patented Mar. 19 1889.

WITNESSES, IJV V'EJV'TOR A141, .dttorney UNITE TATES PATIE T rrIcE.

CHARLES E. EeAN, or COLUMBUS, oI-IIo, ASSIGNOR or ONE-TENTH TO N. w.HALLEY, or TIPTON, INDIANA.

INCANDESCENT-ELECTRlC -LAMP SOCKET.

SPECIFICATION forming part of Letters Patent No. 399,748, dated March19, 1889.

Application filed July 11, 1888. Serial N0- 7 -l T0 aZZ whom it mayconcern:

Be it known that I, CHARLES E. EGAN, a citizen of the United States,residing at O0- lumbus, in the county of Franklin and State of Ohio,have invented certain new and useful Improvements in IncandescentElectric Lamps; and I do declare the following to be a full, clear, andexact description of the invention, such as will enable others skilledin the art to which it appertains to make and use the same, referencebeing had to the accompanying drawings, and to the letters and figuresof reference marked thereon, which form a part of this specification.

My invention relates to incandescent electric lamps, and has for itsobject the production of a lamp which will be cheaper to menu-- factureand will maintain a constant resistance in the lighting-circuit,whetherthe lamp is burning or extinguished.

Other objects of the invention are to dispense with the key or switchmechanism, which render the sockets of the lamps now on the marketexpensive, to provide for the automatic cutting in of a coil equal inresistance to the resistance of the lamp-filament, and to lengthen thelife of the filaments. In lamps as commonly constructed the current isthrown into the filament by means of a switch or key, and mechanism isprovided for establishing the circuit around the lamp when the filamentis cut out. hen the lamp is extinguished, the resistance of its filamentis subtracted from the whole resistance of the branch in which the lampis located, and when a number of. lamps are cut out the aggregatevariation in resistance becomes so considerable that automaticregulation of the current to correspond to the variable resistance ofthe consuming-circuit becomes necessary. One of the great difficultiesin the application of chemical or galvanic generators of electricity toelectric lighting finds its origin in this change of resistance. Thecurrent remaining constant when any considerable number of lamps are cutout, the resistance is so reduced that the remaining lamps are incapableof carrying the whole current, and they therefore burn at a degree ofincandescence which soon destroys the filaments.

It is the object of my invention to overcome this difficulty bypreserving the resistance of the consuming-circuit at an invariablequantity.

To these ends my invention consists of an 5 5 incandescent lamp in whichthe circuit through the filament may be made and broken and the lampfirmly secured in its socket by simply manipulating the body of thelamp, no key being used.

My invention also consists in cutting in a resistance equal to theresistance of the filament by the mere act of extinguishing the lamp.

The invention also embodies certain structural features which willhereinafter be described in this specification, and then definitelyindicated in the appended claims.

In the accompanying drawings, which illustrate my invention, Figure 1 isa side eleva tion of an incandescent lamp made in accordance with myimprovements. Fig. 2 is a side elevation, the socket being shown insection on a larger scale than Fig. 1. Fig. 3 is a plan view of thecontact-springs for shifting the current and maintaining the lamp in thesocket.

Reference being had to the drawings, 1 is the bulb of a lamp of whichthe stem 2 fits a contracted portion of a socket or casing, This casingis provided with a series of slots through which screws 12 pass into aninsulating-support of vulcanized fiber. The base of the lamp, which isprovided with a threaded opening to facilitate attachment to a bracket,8 5

is secured to the insulating-support by the same screws and in the samemanner as the casing On the insulating-support 4 are se-' cured fourmetallic springs, 5 6 13 14:, which are of such a height that their bentterminals will engage headed pins 7 S, projecting from the stem of thelamp, as shown in Fig. 2. These springs, when free to act, approach eachother diametrically, so that they lie closer than the distance betweenthe heads of the pins 7 8. The free ends of the springs are bent atright angles to the main portions and lie in a position transverse tothe length of the socket. These ends are made flaring and are providedwith a circular recess and bev- IOO eled sides, as shown in Fig. 3, sothat when the lamp is turned in its socket the stems of the pins 7 8 maybe forced between springs 5 and 6 or 13 and 14, in which position thesprings will engage the pins with an elastic pressure and the lamp willbe firmly held in the socket. Between the springs 5 and 6 metallic posts9 and 10 are secured to the insulating-base 4. These posts are providedat their free ends with adj ustingscrews or other devices, as shown inFig. 2, so that contact can be made with springs 5 and 6 when the lampis removed from the socket. These posts are in electric connection withthe resistance-coil 11, having a resistance equal to that of thelampfilament. The springs 5 and 6 are electrically connected withthesupply-circuit, while the springs 13 and 14 are not in circuit atall.

The operation will now be understood. When the lamp is placed incircuit, the socket is removed and the adjusting-screws are set so thatcontact will be made with the springs 5 and 6. The stem is then insertedin the socket and the pins 7 and 8 forced into engagement with eitherpair of springs. When the pins are engaged by springs 13 and 14, springs5 and 6 are forced by their resiliency into electric contact with theadj usting-screws on the posts 10 and 11, and the circuit passes throughthe flexible conductors, springs 5 and 6, contacts on posts 9 and 10,and the resistance-coil. If now it be desired to light the lamp, thebulb is grasped by the hand and given a quarter-turn, which brings thepins 7 and 8 into contact with springs 5 and 6, forcing the springsapart and rupturing their connection with the adjusting devices on posts9 and 10. This ruptures the circuit through the resistance-coil andthrows the current through the lamp-filament. It will thus be seen thata key is entirely dispensed with, yet the same result is accomplishedwith equal or greater efficiency. It will also be seen that whether thelamp is burning or extinguished the same resistance will be interposedin the consuming-circuit.

A very important incident flowing from the structure above described isthat in manipulating the lamp the headed pins which form the terminalsof the filament will be frequently changed in lighting or extinguishinga lamp-that is to say, the filament-terminals will reverse position withreference to the supply-conductors, so that the current will passthrough the filament in reverse directions from time to time. It is wellknown that the life of the filaments is shortened by reason of the wearat the positive side, due to an apparent translation of the particles ofcarbon with the current toward the negative terminal. This unevenness ofwear produces a weak point in the filament, which cracks and destroysthe usefulness of the entire lamp. l/Vith my lamp, however, the wear maybe rendered absolutely even by always turning the lamp in the samedirection, a practice a consumer will be sure to follow when he learnsthat it will cheapen the cost of his light. In this way the lamp itselfis made to serve as a current-reverser or polechanger for the currentwhich passes through the filaments.

Having thus described my invention, what I claim, and desire to secureby Letters Patent, 1s-

1. In an incandescent electric lamp, the combination of a socket adaptedto fit over the stem of the lamp, spring-jaws provided withgripping-faces within the socket in permanent electrical connection withthe opposite sides of the supply-circuit, and metallic projections onits stem in electrical connection with the filament adapted to beengaged by the jaws and hold the lamp firmly in the socket, whereby thelamp may be lighted or extinguished by rotating the globe.

2. In an incandescent electric lamp, the

combination of a socket adapted to fit over the stem of the lamp, two ormore pairs of diametrically-opposite sprin g-jaws within the socket,metallic projections on the stem in electrical connection with thefilament adapted to be engaged by either pair of jaws, and conductorsleading from one pair of jaws to the outside of the socket, whereby whenthe lamp is in a supply-circuit it may be lighted or extinguished bypartially rotating the bulb. I

3. In an incandescent electric lamp, the combination, with the socket,of two or more pairs of spring-jaws within the same, projections on thelamp-stem electrically connected with the filament adapted to be engagedby either pair of jaws, contacts in operative relation to one pair of vjaws and engaged by the same when the filament is out of circuit, and aresistance equal to the lamp-filament between the contacts, wherebythelamp may be extinguished by partially rotating its bulb and theresistance thrown into circuit.

4. In an incandescent electric lamp, the combination of a socket adaptedto fit over the stem of the lamp, spring-jaws within the socket, andmetallic projections on the stem electrically connected with thefilament, said jaws being provided with gripping-faces adapted to engagethe projections when the lampglobe is turned in either direction,whereby the lamp may be secured firmly in its socket, lighted orextinguished, and the current through the filament reversed by simplyturning the globe, as and for the purpose set forth.

In testimony whereof I afiix my signature in presence of two witnesses.

CHARLES E. EGAN.

Witnesses:

M. P. CALLAN, II. C. WISE.

